Power booting sequence control system and control method thereof

ABSTRACT

The present invention discloses a power booting sequence control system and the control method thereof, which optimizes a power booting sequence of a plurality of power switches in an integrated circuit. An initial module initializes a target charge value, a preset current budget and a plurality of time intervals. A current lookup module obtains a booting current across a power switch from a built-in current lookup table. A first computing unit and a second computing unit compute a first and a second power switch numbers respectively. A processing module selects the small number of the first and the second power switch number to get a maximum number of power booting switches under the time intervals, and opens the maximum number of the power booting switches. Therefore, the system keeps the in-rush current value under the preset current budget and speeds up the ramp-up time in a power booting state.

BACKGROUND

1. Technical Field

The present invention relates to a power booting sequence control systemand a control method thereof, more specifically to a power bootingsequence control system and a control method thereof of each powerswitch of element blocks in an integrated circuit.

2. Background

The use of power gating to remove the power supply to portions of anintegrated circuit is the most effective way to reduce leakage, as amethod to further reduce power consumption by inactive circuitry.However, powering up circuitry can have various problems includingdynamic IR drop, in-rush current and other problems than can lead topower loss or improper chip operation. Even more seriously, huge in-rushcurrent may also result in on-chip low dropout (LDO) voltage regulatorsor some IPs can not work well. Therefore, the management of the powerbooting usually further design an on-chip power gating in the integratedcircuit to control the open or close of the power switch of each elementblock in the integrated circuit.

Moreover, due to a need of low power consumption in many electronicproducts now, requirements for the power control of the integratedcircuit are stricter, that is, the location and the time of each powerswitch in the controlled circuits are exacter than before. However, theway of power booting at present usually causes the in-rush current valuetoo large and rising speed of the voltage not rapid enough in a state ofsequentially turning on the power, and then causes many unexpectedproblems on the design of the integrated circuit; therefore, theperformance of the integrated circuit is affected. Hence, a need ofdesigning an ideal power booting sequence control system in anintegrated circuit and a control method thereof is an urgent issue thatcan be applied to the business.

SUMMARY

In view of the problems in the art above, the object of the presentinvention is to provide a power booting sequence control system and acontrol method thereof to solve the problems that the way of powerbooting at present causes the in-rush current value too large and risingspeed of the voltage not rapid enough in a power booting state.

According to the object of the present invention, the present inventionprovides a power booting sequence control system, being used to optimizea power booting sequence of a plurality of power switches in anintegrated circuit. The power booting sequence control system comprisesan initial module, a current lookup module, a first computing unit, asecond computing unit, and a processing module. The initial moduleinitializes a target charge value, a preset current budget, and aplurality of time intervals. The current lookup module obtains adifferent voltage value by subtracting an estimate voltage value from asupply voltage value, and obtains a booting current of each the powerswitch from a built-in current lookup table based on the differentvoltage value. The first computing unit connects with the initialmodule, and computes a first power switch number of each the powerswitch opened in sequence based on the specified timing window file,which determines the exact arrival time for each power switch instance,if it is provided. Wherein, the timing window file is optional. Thesecond computing unit connects with the initial module and the currentlookup module, and computes an opened second power switch number basedon the booting current in the every time interval if being less than thepreset current budget. The processing module connects with the initialmodule, the current lookup module, the first computing unit, and thesecond computing unit, and the processing module selects a small numberof the first and the second power switch numbers to get a maximum numberof the power booting switch in the every time interval if being lessthan the preset current budget, and opens the maximum number of thepower booting switch.

The processing module further computes an accumulated current value, anaccumulated charge value, and an accumulated voltage value.

The current lookup module, the first computing unit and the secondcomputing unit produce the renewed booting current, the renewed firstpower switch number, and the renewed second power switch numberrespectively if the accumulated charge value is less than the targetcharge value.

The processing module selects a small number of the renewed first andthe renewed second power switch numbers to get a sequential number ofpower booting switch in the every time interval if being less than thepreset current budget, computes the renewed accumulated current value,the renewed accumulated charge value, and the renewed accumulatedvoltage value, and opens the sequential number of the power bootingswitch.

If the accumulated charge value is more than or equal to the targetcharge value, the processing module controls the current lookup module,the first computing unit, and the second computing unit to stopproducing the renewed booting current, the renewed first power switchnumber, and the renewed second power switch number.

According to the object of the present invention, the present inventionfurther provides a method of controlling a power booting sequence,comprising steps of: providing an initial module for initializing atarget charge value, a preset current budget, and a plurality of timeintervals; providing a current lookup module for obtaining a differentvoltage value by subtracting an estimate voltage value from a supplyvoltage value, and obtaining a booting current of each the power switchfrom a built-in current lookup table; providing a first computing unitfor computing a first power switch number of each the power switchopened in sequence based on the every time interval; providing a secondcomputing unit for computing an opened second power switch number basedon the booting current in the every time interval if being less than thepreset current budget; and providing a processing module for selecting asmall number of the first and the second power switch numbers to get amaximum number of power booting switch in the every time interval ifbeing less than the preset current budget, and opening the maximumnumber of the power booting switch.

The method further comprises a step of computing an accumulated currentvalue, an accumulated charge value, and an accumulated voltage value bythe processing module after the processing module obtains the maximumnumber of the power booting switch in the every time interval.

The method further comprises a step of producing the renewed bootingcurrent, the renewed first power switch number, and the renewed secondpower switch number respectively by the current lookup module, the firstcomputing unit and the second computing unit if the accumulated chargevalue is less than the target charge value.

The method further comprises a step of selecting a small number of therenewed first and the renewed second power switch numbers by theprocessing module to get a sequential number of power booting switch inthe every time interval if being less than the preset current budget,computing the renewed accumulated current value, the renewed accumulatedcharge value, and the renewed accumulated voltage value, and opening thesequential number of the power booting switch.

The method the method further comprising a step of controlling thecurrent lookup module, the first computing unit, and the secondcomputing unit by the processing module to stop producing the renewedbooting current, the renewed first power switch number, and the renewedsecond power switch number if the accumulated charge value is more thanor equal to the target charge value,

According to the object of the present invention, the present inventionfurther provides another power booting sequence control system, beingused to optimize a power booting sequence of a plurality of powerswitches in an integrated circuit. The power booting sequence controlsystem comprises an initial module, a current lookup module, a computingunit, and a processing module. The initial module initializes a targetcharge value, a preset current budget, and a restriction power switchcluster size. The current lookup module obtains a different voltagevalue by subtracting an estimate voltage value from a supply voltagevalue, and obtains a booting current of each the power switch from abuilt-in current lookup table based on the different voltage value. Thecomputing unit connects with the initial module and the current lookupmodule, and computes a flexible time interval based on the bootingcurrent and the restriction power switch cluster size if being less thanthe preset current budget. The processing module connects with theinitial module, the current lookup module, and the computing unit, andthe processing module opens the restriction power switch cluster sizeand stops opening any of the power switches in the flexible timeinterval.

The processing module further computes an accumulated current value, anaccumulated charge value, and an accumulated voltage value.

The current lookup module and the computing unit produce the renewedbooting current and the renewed flexible time interval respectively ifthe accumulated charge value is less than the target charge value.

The processing module further computes the renewed accumulated currentvalue, the renewed accumulated charge value, and the renewed accumulatedvoltage value, opens the restriction power switch cluster size, andstops opening any of the power switches in the flexible time interval.

If the accumulated charge value is more than or equal to the targetcharge value, the processing module controls the current lookup moduleand the computing unit to stop producing the renewed booting current andthe renewed flexible time interval.

According to the object of the present invention, the present inventionfurther provides a method of controlling a power booting sequence,comprising steps of: providing an initial module for initializing atarget charge value, a preset current budget, and a restriction powerswitch cluster size; providing a current lookup module for obtaining adifferent voltage value by subtracting an estimate voltage value from asupply voltage value, and obtaining a booting current of each the powerswitch from a built-in current lookup table based on the differentvoltage value; providing a computing unit for computing a flexible timeinterval based on the booting current and the restriction power switchcluster size if being less than the preset current budget; and providinga processing module for opening the restriction power switch clustersize and stopping opening any of the power switches in the flexible timeinterval.

The method further comprising a step of: computing an accumulatedcurrent value, an accumulated charge value, and an accumulated voltagevalue by the processing module after the processing module obtains theflexible time interval.

The method further comprising a step of: producing the renewed bootingcurrent and the renewed flexible time interval respectively by thecurrent lookup module and the computing unit if the accumulated chargevalue is less than the target charge value.

The method further comprising a step of: computing the renewedaccumulated current value, the renewed accumulated charge value, and therenewed accumulated voltage value, opening the restriction power switchcluster size, and stopping opening any of the power switches at theflexible time interval by the processing module.

The method further comprising a step of: controlling the current lookupmodule and the computing unit to stop producing the renewed bootingcurrent and the renewed flexible time interval by the processing moduleif the accumulated charge value is more than or equal to the targetcharge value

In concluding, the power booting sequence control system and a controlmethod thereof of the present invention include one or many advantagesbelow:

-   -   (1) Each power switch of the element blocks in the integrated        circuit can keep the in-rush current value under the preset        current budget in a power booting state.    -   (2) Each power switch of the element blocks in the integrated        circuit can increase the rising speed of the voltage in a power        booting state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a power booting sequence controlsystem according to first embodiment of the present invention.

FIG. 2 is a diagram showing a booting sequence of the power bootingsequence control system according to the first embodiment of the presentinvention.

FIG. 3 is a block diagram showing a power booting sequence controlsystem according to second embodiment of the present invention.

FIG. 4 is a diagram showing booting sequence of the power bootingsequence control system according to the second embodiment of thepresent invention.

FIG. 5 is schematic diagram showing the accumulated current value of thepower booting sequence control system according to two embodiments ofthe present invention.

FIG. 6 is schematic diagram showing the accumulated current value of thepower booting sequence control system according to two embodiments ofthe present invention.

FIG. 7 is a flowchart showing a method of controlling a power bootingsequence according to the first embodiment of the present invention.

FIG. 8 is a flowchart showing a method of controlling a power bootingsequence according to the second embodiment of the present invention.

DETAILED DESCRIPTION

Please refer to the related drawings below, which illustrate embodimentsof a power booting sequence control system and a control method thereofaccording to the present invention. For easy understanding, the sameelement will be given the same element number in the followingembodiments.

Please refer to FIG. 1, which is a block diagram showing a power bootingsequence control system according to first embodiment of the presentinvention. As shown in the drawing, a power booting sequence controlsystem 1 includes an initial module 20, a current lookup module 21, afirst computing unit 22, a second computing unit 23, and a processingmodule 24.

The power booting sequence control system 1 is used to optimize a powerbooting sequence of a plurality of power switches in an integratedcircuit. The initial module 20 initializes a target charge value, apreset current budget, and a fixed time interval. The target chargevalue is a number that multiplies a supply voltage value by a pluralityof capacitance values of element blocks in the integrated circuit, andthe preset current budget and time interval can set different valuedepended on a need of the user. However, the time intervals that set bythe user all have equal time length.

Furthermore, the current lookup module 21 obtains a different voltagevalue by subtracting an estimate voltage value from the supply voltagevalue, and obtains a booting current of each the power switch from abuilt-in current lookup table based on the different voltage value. Thebooting current of each the power switch is the booting current acrossthe p-type or n-type metal oxide semiconductor field effect transistor(MOSFET), wherein the estimate voltage value is an estimate analogvoltage value obtained from interpolating the two data built-in thecurrent lookup module 21.

The first computing unit 22 connects with the initial module 20, andcomputes a first power switch number of each the power switch opened insequence based on the deterministic timing window file. The timingwindow file in the embodiment of present invention is optional.

The second computing unit 23 connects with the initial module 20 and thecurrent lookup module 21, and computes an opened second power switchnumber based on the booting current in each the time interval if beingless than the preset current budget.

The processing module 24 connects with the initial module 20, thecurrent lookup module 21, the first computing unit 22, and the secondcomputing unit 23. The processing module 24 selects a small number ofthe first and the second power switch numbers, and obtains anaccumulated current value that multiplies the small number by thebooting current, wherein the accumulated current value is less than thepreset current budget. In other words, the maximum number of powerbooting switch in the time interval is obtained. The processing module24 then computes an accumulated charge value based on the current areaand obtains an accumulated voltage value by dividing the obtainedaccumulated charge value by the plurality of capacitance values ofelement blocks in the integrated circuit. The processing module 24 thenopens the maximum number of the power booting switch in the timeinterval.

If the accumulated charge value is less than the target charge value,the power booting sequence control system 1 will repeat the motions ofevery module and unit described above. Hence, the current lookup module21, the first computing unit 22 and the second computing unit 23 willproduce the renewed the booting current, the renewed first power switchnumber, and the renewed second power switch number respectively based onthe foregoing description. The processing module 24 selects a smallnumber of the renewed first and the renewed second power switch numbers,and multiplies the small number by the renewed the booting current. Thenthe original accumulated current value is added and the renewedaccumulated current value is obtained, wherein the renewed accumulatedcurrent value is also less than the preset current budget. Therefore,the small number selected from the renewed first and the renewed secondpower switch numbers by the processing module 24 is the maximumsequential number of the power booting switch. The processing module 24then computes a renewed accumulated charge value based on the renewedcurrent area, and obtains a renewed accumulated voltage value bydividing the renewed accumulated charge value by the plurality ofcapacitance values of element blocks in the integrated circuit. Afterthat, the processing module 24 will open maximum sequential number ofthe power booting switch. Therefore, if the renewed accumulated chargevalue is less than the target charge value, the power booting sequencecontrol system 1 will repeat the motions described above.

If the renewed accumulated charge value is more than or equal to thetarget charge value, the current lookup module 21, the first computingunit 22, and the second computing unit 23 will stop producing therenewed booting current, the renewed first power switch number, and therenewed second power switch number. The power booting sequence controlsystem 1 will stop the motions described above.

Please refer to FIG. 2, which is a diagram showing the booting sequenceof the power booting sequence control system according to the firstembodiment of the present invention. As shown in the drawing, the firstcomputing unit 22 and the second computing unit 23 produce the firstpower switch number and the second power switch number in sequence inthe time interval based on the equal time interval that presets 10nanosecond. The processing module 24 selects small numbers of the firstand the second power switch numbers in the time intervals to get maximumnumber of power booting switch, such as 167, 4, 9, 10, 13, 19, 40 etc.,in the time interval of every 10 nanosecond. The processing module 24then boots the power switches in sequence until the renewed accumulatedcharge value is more than or equal to the target charge value, and powerbooting of the element blocks in the integrated circuit is finished.

Please refer to FIG. 3, which is a block diagram showing the powerbooting sequence control system according to second embodiment of thepresent invention. As shown in the drawing, the power booting sequencecontrol system 3 includes an initial module 30, a current lookup module31, a computing unit 32, and a processing module 33. The power bootingsequence control system 3 is used to optimize a power booting sequenceof a plurality of power switches in an integrated circuit. It must haveto say first that the motions of the second embodiment are the same asthe motions of the first embodiment descripted above so that it isn't togive unnecessary details.

The difference between the first and the second embodiments is that: theinitial module 30 initializes to set a target charge value, a presetcurrent budget, and a restriction power switch cluster size that thenumber is fixed. The computing unit 32 computes a flexible time intervalbased on the booting current and the restriction power switch clustersize if being less than the preset current budget.

The processing module 33 connects with the initial module 30, thecurrent lookup module 31, and the computing unit 32. The processingmodule 33 opens the restriction power switch cluster size that thenumber is fixed and stops opening any of the power switches in theflexible time interval. In addition, the processing module 33 computesthe accumulated charge value based on the current area and obtains anaccumulated voltage value by dividing the obtained the accumulatedcharge value by the plurality of capacitance values of the elementblocks in the integrated circuit.

If the accumulated charge value is less than the target charge value,the power booting sequence control system 3 will repeat the motions ofevery module and unit described above. Hence, the current lookup module31 and the computing unit 32 produce the renewed booting current and theflexible time interval respectively. The processing module 33 thencomputes a renewed accumulated charge value based on a new current area,and obtains a renewed accumulated voltage value by dividing the renewedaccumulated charge value by the plurality of capacitance values of theelement blocks in the integrated circuit. After that, the processingmodule 33 opens the restriction power switch cluster size that thenumber is fixed and stops opening any of the power switches in theflexible time interval. Therefore, if the renewed accumulated chargevalue is less than the target charge value, the power booting sequencecontrol system 3 will repeat the motions described above.

If the renewed accumulated charge value is more than or equal to thetarget charge value, the current lookup module 31 and the computing unit33 will stop producing the renewed booting current and the flexible timeinterval. The power booting sequence control system 3 will stop themotions described above.

Please refer to FIG. 4, which is a diagram showing booting sequence ofthe power booting sequence control system according to second embodimentof the present invention. As shown in the drawing, the computing unit 32produces the flexible time interval one by one in sequence based on thefifty power switch cluster that the number is fixed. The processingmodule 33 then boots the fixed fifty power switches in sequence based onthe flexible time interval one by one, such as 100 picoseconds, 100picoseconds, 100 picoseconds, 29.3 nanosecond, 29.3 nanosecond, and 15.8nanosecond etc., until the renewed accumulated charge value is more thanor equal to the target charge value, and power booting of the elementblocks in the integrated circuit is finished.

Please refer to FIGS. 5 and 6 together, which are schematic diagramsshowing the accumulated current value and the accumulated voltage valueof the power booting sequence control system according to twoembodiments of the present invention.

As shown in FIG. 5, doted line is the accumulated current value producedby the power booting in the conventional integrated circuit, which opensone power switch at one time in sequence. After the accumulated currentvalue increases gradually to a maximum value based on the opening timeinterval, it will decrease to a low value and the power booting of theelement block in the integrated circuit is completed. Solid line is theaccumulated current value produced by the power booting sequence controlsystem in the present invention. The accumulated current value iscontinually kept a preset current budget that is set initially at thestart and decreased to a low value after that, and the power booting ofthe element block in the integrated circuit is completed. From thediagram, we can understand that the in-rush current can be controlled bythe power booting sequence control system in the present invention andbe kept under a preset current budget.

As shown in FIG. 6, doted line is the accumulated voltage value producedby the power booting in the conventional integrated circuit, and solidline is the accumulated voltage value produced by the power bootingsequence control system in the present invention. From the diagram, wecan understand that the accumulated voltage value produced by the powerbooting sequence control system in the present invention can reach to atarget value rapider than the accumulated voltage value produced by thepower booting in the conventional integrated circuit. In other words,the rising speed of the voltage in the element block of the integratedcircuit is increment.

FIG. 7 is a flowchart showing a method of controlling a power bootingsequence according to first embodiment of the present invention. Amethod of controlling the power booting sequence is used to optimize apower booting sequence of a plurality of power switches in an integratedcircuit. Please refer to FIG. 7, firstly as shown in step S71, whichprovides an initial module for initializing a target charge value, apreset current budget, and a plurality of time intervals. In step S72,which provides a current lookup module for obtaining a different voltagevalue by subtracting an estimate voltage value from a supply voltagevalue, and obtains a booting current of each the power switch from abuilt-in current lookup table. In step S73, which provides a firstcomputing unit for computing a first power switch number of each thepower switch opened in sequence based on the deterministic timing windowfile (optional). In step S74, which provides a second computing unit forcomputing an opened second power switch number based on the bootingcurrent in each fixed time interval if being less than the presetcurrent budget. In step S75, which provides a processing module forselecting a small number of the first and the second power switchnumbers to get a maximum number of power booting switch in every thetime interval if being less than the preset current budget, computing anaccumulated current value, an accumulated charge value, and anaccumulated voltage value, and opening the maximum number of the powerbooting switch.

Then as shown in step S76, the power booting sequence control systemmust determine that the accumulated charge value and the target chargevalue which one is bigger. If the accumulated charge value is less thanthe target charge value, step will return to S72 and repeat the steps.And If the accumulated charge value is more than or equal to the targetcharge value, go to step S77, which provides the processing module forcontrolling the current lookup module, the first computing unit, and thesecond computing unit to stop producing the renewed booting current, therenewed first power switch number, and the renewed second power switchnumber.

FIG. 8 is a flowchart showing a method of controlling a power bootingsequence according to second embodiment of the present invention. Themethod of controlling the power booting sequence is used to optimize apower booting sequence of a plurality of power switches in an integratedcircuit. Please refer to FIG. 8, firstly as shown in step S81, whichprovides an initial module for initializing a target charge value, apreset current budget, and a restriction power switch cluster size. Instep 82, which provides a current lookup module for obtaining adifferent voltage value by subtracting an estimate voltage value from asupply voltage value, and obtaining a booting current of each the powerswitch from a built-in current lookup table based on the differentvoltage value. In step 83, which provides a computing unit for computinga flexible time interval based on the booting current and therestriction power switch cluster size if being less than the presetcurrent budget. In step 84, which provides a processing module forcomputing an accumulated current value, an accumulated charge value, andan accumulated voltage value, opening the restriction power switchcluster size, and stopping opening any of the power switches in theflexible time interval.

Then as shown in step S85, the power booting sequence control systemmust determine that the accumulated charge value and the target chargevalue which one is bigger. If the accumulated charge value is less thanthe target charge value, step will return to S82 and repeat the steps.And If the accumulated charge value is more than or equal to the targetcharge value, go to step S86, which provides the processing module forcontrolling the current lookup module and the computing unit to stopproducing the renewed booting current and the renewed flexible timeinterval.

Finally, the power booting sequence control system and the controlmethod thereof of the present invention is not limit to the twoembodiments. That is to say, the obtained power switch number in fixedtime interval in the first embodiment and the flexible time intervalobtained from the restriction power switch cluster size that the numberis fixed in the second embodiment, they can perform in the power bootingsequence control system and the control method thereof in the presentinvention with each other at the same time. In other words, theembodiments of the present invention is not limited as long as theaccumulated current value is less than the preset current budget, andthe performance of which is like the description above so that it isn'tto give unnecessary details.

In concluding, each power switch of the element blocks in the integratedcircuit can keep the in-rush current value under the preset currentbudget and can increase the rising speed of the voltage in a powerbooting state by using the power booting sequence control system and thecontrol method thereof.

The foregoing description is only used for example not for restriction.Any equivalent modifications and substitutions which not depart from thespirit and the scope of the present invention should all be included inthe claim below.

What is claimed is:
 1. A power booting sequence control system, beingused to optimize a power booting sequence of a plurality of powerswitches in an integrated circuit, comprising: an initial moduleinitializing a target charge value, a preset current budget, and aplurality of time intervals; a current lookup module obtaining adifferent voltage value by subtracting an estimate voltage value from asupply voltage value, and obtaining a booting current of each the powerswitch from a built-in current lookup table based on the differentvoltage value; a first computing unit connecting with the initialmodule, and computing a first power switch number of each the powerswitch opened in sequence based on the every time interval; a secondcomputing unit connecting with the initial module and the current lookupmodule, and computing an opened second power switch number based on thebooting current in the every time interval if being less than the presetcurrent budget; and a processing module connecting with the initialmodule, the current lookup module, the first computing unit, and thesecond computing unit, wherein the processing module selects a smallnumber of the first and the second power switch numbers to get a maximumnumber of the power booting switch in the every time interval if beingless than the preset current budget, and opens the maximum number of thepower booting switch, wherein the processing module further obtains anaccumulated current value that multiplies the small number by thebooting current, wherein the accumulated current value is less than thepreset current budget.
 2. The system according to claim 1, wherein theprocessing module further computes an accumulated charge value, and anaccumulated voltage value.
 3. The system according to claim 2, whereinthe current lookup module, the first computing unit and the secondcomputing unit produce the renewed booting current, the renewed firstpower switch number, and the renewed second power switch numberrespectively if the accumulated charge value is less than the targetcharge value.
 4. The system according to claim 3, wherein the processingmodule selects a small number of the renewed first and the renewedsecond power switch numbers to get a sequential number of power bootingswitch in the every time interval if being less than the preset currentbudget, computes the renewed accumulated current value, the renewedaccumulated charge value, and the renewed accumulated voltage value, andopens the sequential number of the power booting switch.
 5. The systemaccording to claim 4, wherein if the accumulated charge value is morethan or equal to the target charge value, the processing module controlsthe current lookup module, the first computing unit, and the secondcomputing unit to stop producing the renewed booting current, therenewed first power switch number, and the renewed second power switchnumber.
 6. A method of controlling a power booting sequence, being usedto optimize a power booting sequence of a plurality of power switches inan integrated circuit, comprising steps of: providing an initial modulefor initializing a target charge value, a preset current budget, and aplurality of time intervals; providing a current lookup module forobtaining a different voltage value by subtracting an estimate voltagevalue from a supply voltage value, and obtaining a booting current ofeach the power switch from a built-in current lookup table; providing afirst computing unit for computing a first power switch number of eachthe power switch opened in sequence based on the every time interval;providing a second computing unit for computing an opened second powerswitch number based on the booting current in the every time interval ifbeing less than the preset current budget; and providing a processingmodule for selecting a small number of the first and the second powerswitch numbers to get a maximum number of power booting switch in theevery time interval if being less than the preset current budget, andopening the maximum number of the power booting switch, wherein theprocessing module further obtains an accumulated current value thatmultiplies the small number by the booting current, wherein theaccumulated current value is less than the preset current budget.
 7. Themethod of controlling a power booting sequence according to claim 6,wherein after the processing module obtains the maximum number of thepower booting switch in the every time interval, the method furthercomprising a step of: computing an accumulated charge value, and anaccumulated voltage value by the processing module.
 8. The method ofcontrolling a power booting sequence according to claim 7, wherein ifthe accumulated charge value is less than the target charge value, themethod further comprising a step of: producing the renewed bootingcurrent, the renewed first power switch number, and the renewed secondpower switch number respectively by the current lookup module, the firstcomputing unit and the second computing unit.
 9. The method ofcontrolling a power booting sequence according to claim 8, furthercomprising a step of: selecting a small number of the renewed first andthe renewed second power switch numbers by the processing module to geta sequential number of power booting switch in the every time intervalif being less than the preset current budget, computing the renewedaccumulated current value, the renewed accumulated charge value, and therenewed accumulated voltage value, and opening the sequential number ofthe power booting switch.
 10. The method of controlling a power bootingsequence according to claim 9, wherein if the accumulated charge valueis more than or equal to the target charge value, the method furthercomprising a step of: controlling the current lookup module, the firstcomputing unit, and the second computing unit by the processing moduleto stop producing the renewed booting current, the renewed first powerswitch number, and the renewed second power switch number.
 11. A powerbooting sequence control system, being used to optimize a power bootingsequence of a plurality of power switches in an integrated circuit,comprising: an initial module initializing a target charge value, apreset current budget, and a restriction power switch cluster size; acurrent lookup module obtaining a different voltage value by subtractingan estimate voltage value from a supply voltage value, and obtaining abooting current of each the power switch from a built-in current lookuptable based on the different voltage value; a computing unit connectingwith the initial module and the current lookup module, and computing aflexible time interval based on the booting current and the restrictionpower switch cluster size if being less than the preset current budget;and a processing module connecting with the initial module, the currentlookup module, and the computing unit, the processing module opening therestriction power switch cluster size and stopping opening any of thepower switches in the flexible time interval, wherein the processingmodule further obtains an accumulated current value that multiplies therestriction power switch cluster size by the booting current, whereinthe accumulated current value is less than the preset current budget.12. The system according to claim 11, wherein the processing modulefurther computes an accumulated charge value, and an accumulated voltagevalue.
 13. The system according to claim 12, wherein the current lookupmodule and the computing unit produce the renewed booting current andthe renewed sequential time interval respectively if the accumulatedcharge value is less than the target charge value.
 14. The systemaccording to claim 13, wherein the processing module further computesthe renewed accumulated current value, the renewed accumulated chargevalue, and the renewed accumulated voltage value, opens the restrictionpower switch cluster size, and stops opening any of the power switchesin the flexible time interval.
 15. The system according to claim 14,wherein if the accumulated charge value is more than or equal to thetarget charge value, the processing module controls the current lookupmodule and the computing unit to stop producing the renewed bootingcurrent and the renewed flexible time interval.
 16. A method ofcontrolling a power booting sequence, being used to optimize a powerbooting sequence of a plurality of power switches in an integratedcircuit, comprising steps of: providing an initial module forinitializing a target charge value, a preset current budget, and arestriction power switch cluster size; providing a current lookup modulefor obtaining a different voltage value by subtracting an estimatevoltage value from a supply voltage value, and obtaining a bootingcurrent of each the power switch from a built-in current lookup tablebased on the different voltage value; providing a computing unit forcomputing a flexible time interval based on the booting current and therestriction power switch cluster size if being less than the presetcurrent budget; and providing a processing module for opening therestriction power switch cluster size and stopping opening any of thepower switches in the flexible time interval, wherein the processingmodule further obtains an accumulated current value that multiplies therestriction power switch cluster size by the booting current, whereinthe accumulated current value is less than the preset current budget.17. The method of controlling a power booting sequence according toclaim 16, wherein after the processing module obtains the flexible timeinterval, the method further comprising a step of: computing anaccumulated charge value, and an accumulated voltage value by theprocessing module.
 18. The method of controlling a power bootingsequence according to claim 17, wherein if the accumulated charge valueis less than the target charge value, the method further comprising astep of: producing the renewed booting current and the renewed flexibletime interval respectively by the current lookup module and thecomputing unit.
 19. The method of controlling a power booting sequenceaccording to claim 18, wherein the method further comprising a step of:computing the renewed accumulated current value, the renewed accumulatedcharge value, and the renewed accumulated voltage value, opening therestriction power switch cluster size, and stopping opening any of thepower switches in the flexible time interval by the processing module.20. The method of controlling a power booting sequence according toclaim 19, wherein if the accumulated charge value is more than or equalto the target charge value, the method further comprising a step of:controlling the current lookup module and the computing unit to stopproducing the renewed booting current and the renewed flexible timeinterval by the processing module.